Overview

The Perko 8501DP is a medium duty battery selector switch for 6 to 32 VDC marine electrical systems, rated for 250 amps continuous duty and 360 amps intermittent duty. It gives you the standard 1, ALL, 2, and OFF positions used to manage two battery banks for engine starting, house loads, or emergency parallel use.

It is built for surface mounting and uses a polycarbonate body with brass terminals in a compact footprint of 5-1/4 in diameter and 2-5/8 in depth. Because it uses the traditional Perko bolt circle, it is often a straightforward replacement when you are swapping out an older selector switch at the helm, in a battery compartment, or near the main DC distribution area.

This 8501DP version is the standard selector model in the 8501 range. It does not include the key lock or alternator field disconnect found on other versions in the same family.

Key features

• Works with 6 to 32 VDC marine electrical systems and is rated for 250 amps continuous and 360 amps intermittent duty.
• 1, ALL, 2, and OFF selector positions let you choose one battery, combine banks, or isolate the system.
• Make-before-break action between 1, ALL, and 2 allows battery-bank changes while the engine is running.
• Ignition-protected construction allows installation in gasoline engine spaces.
• Surface-mount body with a 5-1/4 in diameter and 2-5/8 in depth fits many common battery-switch locations.
• Polycarbonate housing with brass terminals stands up well to the damp, vibrating environment found on board.

Installation and setup

This switch is meant to be mounted where it is easy to reach and where battery cable runs can stay as short as practical. That matters on a boat because long cable runs add voltage drop and make a simple battery-selector job harder to troubleshoot later.

In normal use, you can move between 1, ALL, and 2 with the engine running. OFF is different, and engines should be stopped before the switch is turned to that position. On installations with very large battery cables, extra rear clearance may be needed behind the switch body.

Compatibility and fit

This switch is a good match for boats that use two battery banks, such as a start battery and a house battery, and need manual control over which bank is online. It also suits setups where both banks may need to be paralleled for emergency starting.

It fits owners who want the familiar Perko selector layout without stepping up to a keyed version or a model with alternator field disconnect. For repower work, refits, and routine replacement of an older Perko selector, the established mounting pattern is often one of the main reasons this model stays in service on cruising boats, fishing boats, and sailboats.